Improved process for preparing 11beta-hydroxy-fluoro-steroids



a 2,924, iCfi P t nted Fe 9, 1 9

I IMPROVED PROCESS FOR PREPARING llfl-HY- DROXY-FLUORO-STEROIDS 5 Ralph F. Idirschmann, Westfield, and Richard Miller, New

Brunswick, NJ., assignors to Merck & Co., Inc., Rahway, N.J., a corporation of New Jersey t i No Drawing. Application December 30 1955 I 6 Serial No. 556,426 Th t ifi 2 a1 r, e s eroi epoxi es use as starting materi s 16 Claims. (Cl. 260397.45) in this process include known compounds such as 9,11-

. epoxy-4-pregnene-17a,2l-diol-3 20-dione; other steroid d 13, i i a congemed genFrally Wlth the Pro? C-ll epoxides are conveniently prepared by reacting the =E, y foxy 9' of the pregnfme corresponding ll-hydroxy-bromo-steroid with a base." series from the corresponding stero d C-ll epoxide. For example, 9,11 epoXy 1,4 prbgnadiene 17a,21 dib1 i f Partlcularly relates 3? unprovefl method 3,20-dione 21-acetate is prepared by reacting 9a-bro mo- W f= resctmg a stemld epoxlde of the 1,4-pregnadiene- 11,8,17oc,21 -triol-3,20-dione 21-acetate rt sFnes Wlth hydrogen fluonde to PrOdPCe the with sodium methoxide in methanol; the 9a-bromo-1,4- r f e Y r y-( such pregnadiene-l1,9,17a,2ltriol-3,20-dione ZI-acetate may a A 'ia g'g g g' P be prepared by reacting 1,4-pregnadiene-11p,17a,21-triolnim 1 3 9 lllsinaizl Y 3,20-dione 21-acetate with methane sulfonyl chloride to Pr a A W I form 1,4,9(11)-pregnatriene-17a,2l-diol-3,20-dione 21- Whlch Possess extremely 'f local acetate and reacting the latter compound with hypo cort sone-activity and are valuable for alleviating lnflam- 25 bromouS acid. Similarly, 11 g ym qfl mations of the skin resulting from chemical or allergic o1 320 di0ne is prepared by reacting 12" bmmo 4 prbg; lmtants Q? dlseasenene-l1B,2l-diol-3,20-dione with a base such as sodium l leretofore, ll-hydroxy-fluoro-steroids of the pregnane metbbxide in 1; z m n ez series have been prepared by reacting the appropriate nfilbdiowazobibne may be prepared by reacting the steroid C-ll epoxide with anhydrous hydrogen fluoride known 12a bmmo 4 pregnene 21 o1 31lzatrione with m chloroform or wlth aqueous hydrofiuonc acld' Bolth excess semicarbazide to form the 3,20-bis-semicarbazone of these methods have been hozevert eimemely unsaus' reacting the latter with lithium borohydride to produce factory- For example P A 12a-bromo-4- pregnene-l lfl,2l-diol-3,20-dione 3,20-bis- 17a,21.-dihydroxy-pregnene s reacted with anhydrous semicarbazone and reacting this product i a hydrogen fluoride in chloroform, the reaction proceeds dmlyzing agebb 1 4 g i -21- 1.

rather slowly and results in fairly low yields of impure 3,20 dione is likewise prepared by reacting 12wbromo. product. Attempts have been made to accelerate the 1,4 pregnadiene 11b21 dio1 3,20 dione with Sodium metb. speed of the reaction and augment the yield of the deoxide in methanol; h lz -b mo-l,4-pregnadienei d. ll'hydroxy'fluoro'teroid i conducting the Ff llfi,21-diol-3,20-dione may be prepared by microbiologil v g tqums reactlon P aqueous condmfzns 40 cal dehydrogenation of 12u-bromo-4-pregnene-11,3,21- have mfewlse Proved unsitlsflacmry f a f f diol-3,20-dione with Bacillus sphaericus microorganisms. standpoint due to the relative insolubillty of the steroid The steroid epoxides containing a free 2Lalc0hol f m i: aqueogs fl grouping such as 9,11-epoxy-1,4-pregnadiene-17a,21-diold'bwvere accoldance W h Present 3,20-dione, 9,11-epoxy-4-pregnene-l7a,2l-diol-3,20-dione, nvention, that the react on between steroid C-ll epoxblzfi epoxy 4 pregnene m 115,12} Ides and hydrogenfiuonde. p be effected m an army epoxy-1,4-pregnadiene-21-ol-3,20-dione, are reacted with drous reactlon medium which is a mutual solvent for the an acylating agent ag, a lower alkanoic anhydride such reactants, and under reaction conditions which result in as acetic anhydride pmpionic anhydride 3 lower a1ka 5 i a relatively rapid reaction rate and in a high yield of the no 6 b yl halide such as tertiary butyl-acetyl chloride, in the f f 12 yfluorostemld by conduct presence of pyridine to form the corresponding 21-ester ingithe react on in the presence of a compound formed such as glbepoxs, 1,4 pregnadiene 17a21 diol 3,20 by the reaction of hydrogen fluoride with a substance dione zLacetate, 9,ll epoxy 4 Pregnene 17a,21 dio1 which can be characterized as a Lewis base in accord- 32o dione zbpropionate, 11 5,123 epoxy 4 pregnene41 v ance with G. N. Lewis definition of acids and bases as 2 t 1 12 set forth on pages 80-81 of the text, Advanced Organic 3 2i g 33333 z fisig i f ang il ig l ikef pregna mne- Qhemistry, by Wheland (Wiley & Sons 2nd In carrying out the presently invented process, the steroid C-ll epoxide and hydrogen fluoride are brought This reaction between hydrogen fluoride and the steroid together in the Presence of an organic liquid which is a 0-11 epoxide that is a gll'epoxy'stemid (Compound 1 solvent for both the steroid compound and the hydrogen hereinbelow) ,or an lllz'epoxy'steroid (Compound fluoride as, for example, a halogenated hydrocarbon solto produce the correspondmg i vent such as chlorofor, ethylenedichloride, carbon tetra- (Compounds 3 and 4) may be chemlcauy represented chloride, and the'like, said mixture of steroid C-ll (insofar as changes taking place in rings B and C are epoxide, hydrogen fluoride and organic liquid containing a concerned) by followmg chemlcal squamous: minor amount of a compound formed by the reaction of hydrogenfluorideand a Lewis base as set forth in column 1 hereinabove. Since a Lewis base is defined expression includes, in addition to the ordinary bases such. as the metal hydroxides, ammonia and amines, other pro-j ton acceptors such as alcohols, ethers, ketones and the like. It is ordinarily preferred, however, to employ a Lewis base compound 1 Compound 3' which reacts with hydrogen fluoride to form a compound as any substancewhich willact as a proton acceptor, this which is soluble in the organic liquid utilized as the reaction medium as, for example, a lower alkanol such as methanol, ethanol, a dialkyl-tether such as diethyl ether, a cyclic ether such as dioxane, tetrahydrofuran, an amine such as pyridine, and the like. While the compound formed by reacting hydrogen chloride and Lewis base can, in some instances, be added as such to the reaction mix ture 6. g. ammonium fluoride, hydrogen fluoride the compound formed by reaction with a very weakbase such as an alcohol or ether is preferably produced in the reaction mixture by adding the base and hydrogen fluoride directly thereto. The amount of base incorporated in the reaction mixture depends upon its strength, and the optimum amount must be determined in each case; if too large a ratio of base to hydrogen fluoride is used, the acidity of the medium is reduced to such an extent that little reaction, if any, occurs, whereas if the ratio of base to hydrogen fluoride is too -.small,-particular-ly in the case of Weak bases such as tetrahydrofuran, the reaction proceeds with the formation of undesired by-pro'ducts.

his to be understood that the present invention contemplates the utilization, for each Lewis base, of a range of ratios of base to hydrogen fluoride which results in an acidity approximating the acidity range resulting from the optimum ratios of tetrahydrofuran and pyridine set forth hereinbelow. In the case of tetrahydrofuran we prefer to employ a ration of about 1.4 to 2 moles of hydrogen fluoride .per mole of tetrahydrof-uran although somewhat lower or higher ratios can be employed if desired. At a ratio below 0.4 molehydrogenfluoride per mole of tetrahydrofuran, no fiuorohydrjn has beenobtained, only unchanged starting epoxide having been recovered from the reaction mixture. In the case of pyridine the optimum molar ratio of hydrogen fluoride to pyridine is higher than in the caseof tetrahydrofuran i.e. about 1.5 to 2.5. The reaction is ordinarily conducted at .a temperature within the range of about 60 C. to +20 C.; at the higher temperature, the acidity of the mixture is somewhat increased-for a given ratio of hydrogen fluoride to tetra hydrofuran; since the formation of undesired hy-products is reduced by employing a large proportion of Lewis base, we ordinarily conduct the reaction at temperatures below C. and preferably at about 30 C. Under these temperature conditions, the-reaction is usually complete in about 4-5 hours. I

The ll-hydroxy-fluoro-steroid is conveniently recovered by quenching the reaction mixture in a cold mixture of a halogenated hydrocarbon solvent such as chloroform and water (or aqueous carbonate solution) washing the organic solvent layer with aqueous alkaline solution, with aqueous acid and with water, and evaporating the solvent. The ll-hydroxyhuorosteroid is purified by crystallization from an organic solvent e.g. acetone-petroleum ether. In accordance with this procedure there are obtained'9afluoro-ll s-hydroxy-steroids of the pregnane series as for as 2l-lower alkanoates, the ll-acetates, 2l-propionates,

2l-tertia'ry butyl-acetates, and the like, IZOPflUOl'O-IIBJlY- droxy-steroids of the pregnane series as, for example, 12afluoro-4-pregnene-l1B,l7a,21-triol-3,20-di0ne, 12a-fl'uorol-,4pregnadiene-l16,17a,21-triol-3,20-dione, 12a'fluo'ro-4- pregnene-llB,2l-diol 3,20-di0ne, 12u-fiuoro-l,-4'pregn-adiene-l 13,2 1-diol-3,20-dione, -l2a-fluoro 4-pregnene-l7m2l- 4.. these examples are given for purposes of illustration and not of limitation.

Example 1 To a mixture of cc. of chloroform and 60 cc. of tetrahydrofuran, cooled to 330 C., is added 100 cc. of a cold C.) solution of anhydrous hydrogen fluoride in isopropyl alcohol (1:1 wt./wt.). A slurry of 4.022 g. of 9,1l-epoxy-4-pregnene-17a,21-diol-3,20-dione ZI-acetate '(MQP. res-1905c. in -20 cc. of cold chloroform is added and the resulting mixture is maintained at 30 C. for four and one-half hours with repeated shaking. The reaction mixture is allowed to warm, over a period of one hour, to a temperature of +16 C. The reaction mixture is then cooled to -30 C. and then poured into 100 cc. of cold water. About 125 cc. of chloroform is added and the layers are seperated. The aqueous phase is back-extracted with two rte-portions of chloroform. The combined organic layers are washed three times with 1 00 cc.-poftions of a 5% aqueous solution of sodium bicarbonate and twice with water. The chloroform is evaporated in vacuo, and the residual material, suspended in 5 cc. of pyridine and 3 cc. of acetic anhydride, is maintained at C. in an inert atmosphere for about one hour and fifteen minutes. The bulk of the solvents are evaporated in vacuo at 60-65 C, and the residual material is distributed between 50 cc of chlorow form and .25 cc. of 1.25 N aqueous hydrochloric acid solution. The aqueous layer is back-extracted twice with 25 cc. po'r'tion's of chloroform. The combined organic layers are washed three times with 1.25 N aqueous hydrochloric acid solution, twice with water, once with a 5% aqueous solution of sodium bicarbonate, and finally twice with ii'ater. solution is eva orated inv'acuo to a volume of about 1 5 cc., and the concentrated solution is adsorbed on a column of 16 g. of neutral "alumina; the 'ads'orbate is eluted with approximately 85 cc. of chloroform. The elu'ates are filtered, and the filtered solution is evaporated to a volume of about 8 cc.; to the concentrated solution is added 20 cc. "of benzene, and the resulting mixture is allowed to stand for twenty-four hours. The precipitated material is recovered by filtrationand washed twice with benzene triol-3,20-dione Zl-acetate. M.P. 205-2075 C.

Example 2 A solution of 4.020 g. of 9,11-epoxy-4-pregnene-17a,2ldiol-3,20-dione Ell-acetate in 30 ml. of chloroform is chilled and diluted with 8 ml. of filtered tetrahydrofu ran. The solution is cooled to a temperature of approximately *40 C. and is added to 10 ml. of a solution of hydrogen fluoride (anhydrous) in tetrahydro fu-ran (ca. 2:1 wt./wt.) cooled to 70 C. An additional 7 ml. of tetrahydrofuran (temperature -30 C.) is used to aid. in the transfer of the epoxid'esolut'ion. The reaction mixture is kept at '30 C. for three and one-half to four hours, and the temperature of the mixture is then allowed to rise to about C. over a one hour period. The reaction mixture is then cooled to a temperature of about -30 C. and added slowlyto a well-stirred mixture of 25 g. of anhydrous potassium carbonate dissolved in 24 m1. of water, 50 ml. of chloroform and 25 g. of ice. The layers are separated, and the aqueous layers are back-extracted with two 25-ml.-portions. of chloroform. The combined organic layers are washed free of base with water.

in 5 cc. of pyridine and 3 cc. of acetic anhydride, is maintained at 65 C. in an inert atmosphere for about one hour and fifteen minutes. The bulk of the solvents are evaporated in vacuo at 60-65 C., and the residual mate rial is distributed between 50 cc. of chloroform and 25 cc. of 1.25 N aqueous hydrochloric acid solution. The aqueous layer is back-extracted twice with 25 cc.-portions of chloroform. The combined organic layers are washed The or anic layer isfiltered, the filtered The chloroform is evaporated in vacuo, and the residual material, suspended 3,20-dione 21-acetate;

three times with 1.25 N aqueous hydrochloric acid solution, twice with water, once with a 5% 1 aqueous solution of sodium bicarbonate, and finally twice with water. The organic layer is filtered, the filtered solution is evaporated in vacuo to a volume of about cc., and the concentrated solution is adsorbed on a column of 16 g.

Y of neutral alumina; the adsorbate is eluted with approximately 85 cc. of chloroform. The eluates are filtered, and the filtered'solution is evaporated to a volume of about 8 cc.; to the'concentrated solution is added cc. of

benzene, and the resulting mixture is allowed to stand fortwenty-four hours. The precipitated material is recovered by filtration and washed twice with benzene to give about 3.3 g. of 9u-fluoro-4-pregnene-11fi,17a,21-triol- 3,20-dione.

Example 3 mixture is allowedto warm to C. and maintained at that temperature for about four hours. The reaction mixture, maintained at a temperature of about --30 C., is slowly added to a well stirred mixture of 25 g. of

1 anhydrous potassium carbonate dissolved in' 24 ml. of

water, 50ml. of chloroform and 25 g. of ice. The layers are separated, and the aqueous layers are back-extracted with two 25 mL-portionsof chloroform. The combined organic layers are washed free of base with water. The chloroform is evaporated in vacuo, and the residual material, suspended in 5 cc. of pyridine and 3 cc. of acetic anhydride, is maintained at 65 C. in an inert atmosphere for about one hour and fifteen minutes.

The bulk of the solvents are evaporated in vacuo at 60-65 C., and the residual material is distributed between50 (30.015 chloroform and 25 cc. of 1.25 Naqueous hydrochloric acid solution. The aqueous layer is backextracted twice with 25 cc.-portions of chloroform. The combined organic layers are washed three times with 1.25-N aqueous hydrochloric acid solution, twice with water, once with a 5% aqueous solution of sodium bicarbonate, and finally twice with water. -The organic layer is filtered, the filtered solution is evaporated in vacuo to avolume of about 15 cc., and the concentrated solution is adsorbed on a column of 16 g. of neutral alumina;

the adsorbate is eluted with approximately 85 cc. of chloroform. The eluates are filtered, and the filtered solutionis evaporated to avolume of about 8' cc.; to the concentrated solution is added 20 cc. of benzene, and theresulting mixture is allowed to stand for twentyfour-hoursnThe precipitated material is recovered by filtration, washed twice with benzene, dried, anddissolved in about 30 cc. of acetone. The acetone solution is filtered, evaporated to a volume of 10 .cc., 20 cc. of petroleum ether is added to the concentrated solution, and-the resulting mixture is allowed to stand for a period of about 24 hours. The precipitated material is recovered by filtration, washed with a 1:3 mixture of acetonez petroleum ether, and dried to give 3.12 g. of substantially pure 9a-fiuoro-4-pregnene-11,3,17a,21triol- M.P. about 230C. (dec.).

, Example 4 About .19 cc. of pyridine is added cautiously to about ,7 cc. of anhydrous hydrogen fluoride at a temperature of about -60. C. The mixture is allowedto warm until all solids have redissolved and to the resulting solution Additional amounts of ancooling until an orange color persists, and the mixture 60 excess pyridine and acetic anhydride is evaporated, 200

is shaken at room temperature for about four hours. The reaction mixture is then cooled to 30 C. and then poured into 100 cc. of cold water. About 125 cc. of chloroform is added and the layers are separated. The aqueous phase is back-extracted with two cc.-portions of chloroform. The combined organic layers are washed three times with 100 cc.-portions of a 5% aqueous solution of sodium bicarbonate and twice with water. The chloroform is evaporated in vacuo, and the residual material, suspended in 5 cc. of pyridine and 3 cc. of acetic anhydride, is maintained at 65 C. in an inert atmosphere for about one hour and fifteen minutes. The bulk of the solvents are evaporated in vacuo at 60-65 C. and the residual material is distributed between 50 cc. of chloroform and 25 cc. of 1.25 N aqueous hydrochloric acid solution. The aqueous layer is back-extracted twice with 25 cc.-portions of chloroform. The combined organic layers are washed three times with 1.25 N aqueous hydrochloric acid solution, twice with water, once witha 5% aqueous solution of sodium bicarbonate, and finally twice with water. The organic layer is' filter'ed, the filtered solution is evaporated in vacuo to a volume of about 15 cc., and the concentrated solution is adsorbed'on a column of 16 g. of neutral alumina; the adsorbate is eluted with approximately 85 cc. of chloroform. The eluates are filtered, and the filtered solution is evaporated to a volume of about 8 cc.; to the concentrated solution is added 20 cc. of benzene, and the resulting mixture is allowed to stand for twentyfour'hours. The precipitated material is recoveredby filtration and washed'twice with benzene to give about 2-3 g. of 9a-fiuoro-4-pregnene-l1p,17a,21-triol-3,20-dione ZI-acetate. Example 5 f A solution of 12.16 g. (0.0353 mole) of 9,8,1lfl-epoxy- 4-pregnene-l7et-ol-3,20-dione in 106 ml. of chloroform I is added 3.9 g. of solid 9,11-epoxy-4-pregnene-170:,21- diol-3,20-dione 21-acetate. hydrous hydrogen fluoride are added with occasional and 33 ml. of purified tetrahydrofuran is cooled to ca. 30 C. and added to 35.3 ml. of a solution of anhydrous hydrogen fluoride (1.23 mole) in tetrahydrofuran cooled to 70 C. An additional 20' ml. of tetrahydrofuran cooled to 30 C. is used to rinse in the solution of the steroid. The reddish-purple reaction mixture is allowed to warm'to 30 C. and maintained at this temperature for four hours, then allowed to ,warm to room temperature for one hour. The reaction mixture is cooled to 0-5 C. and poured slowly into a stirred mixture of 175 ml. of chloroform, g. of ice, 17.0 g. (1.23 mole) of potassium carbonate and 200 m1 of water; 85 ml. of chloroform is usedto rinse the reaction vessel. The neutralized reaction mixture is diluted further with 400 ml. of water, the mixture is shaken, and the layers separated. The aqueous layer is extracted with two additional portions of chloroform. The combined chloroform extracts are washed with two portions of water, filtered through a bed of anhydrous magnesium sulfate, and the solvents are evaporated in vacuo to give 13.6 g. of a crystalline material.

To this material is added ml. of pyridine and 50 ml. of acetic anhydride, and the resulting mixture is heated for approximately one hour at 6065 C. The

Example 6 p v A a vf 1 acrew-Fr eman.

7 3,20-dione 2l-acetate in 60ml. chloroform and 6.6 ml; tetrahydrofuran is cooled to'-65 C.,- and the cold solution is added dropwise to 6.0 m'l'.' of a mixture of liquid hydrogen fluoride and t'etrahydrofuran (2:1 by weight) at --65 "C. Three ml. chloroform cooled to -60" C. is used to wash in the last traces of steroid. The mixture is maintained at 5 C. for two hours. The reaction mixture is then cooled to -65? C. and added slowly, with stirring, to a mixture of 10 g. potassium carbonate in 50 ml. water and 50 ml. of chloroform maintained at C. The layers are separated, the aqueous phase is extracted further with chloroform, and the combined chloroform extracts are washed twice with water, dried with magnesium sulfate, and evaporated to dryness in vacuo. To the residual material is added 2. ml. pyridine and 1.5 ml. acetic 'anhydride, andthe resulting mixture is maintained at 25C. for 18 hours. Water and chloroform are added to the reaction mixture, the aqueous phase is extracted with chloroform, and the combined chloroform extracts are washed with aqueous potassium carbonate and water, dried with magnesium sulfate, and evaporated to dryness in vacuo. The residual material is crystallized from acetone-ether to give l2a-fiuoro-4-pregnenel1/3,'21-diol-3,20-dione Zl-acetate as a clusterof prisms; M.P. l97-200 C.

Example 7 A solution of 3.00 g. of 95,1iii-epoxy:1,4-pregnadi'enel7a,2l-diol-3,20-dione 21-acetate in 18ml. of chloroform is cooled to about -60 C. Thesolution is poured slowly into a cold (60" C.) solution containing 5.0 ml. of tetrahydrofuran, 3.75 ml. of chloroform, and 7.45 ml. of a solution of hydrogen fluoride in tetrahydrofuran (2:1 by weight); an additional 3.75 ml. of cold chloroform is used to aid in the transfer of the epoxide solution. The solution is maintained at -60 C. for about minutesand then kept at about0 C. forthree and one-half hours The red reaction mixture is recooled to 60" C., then poured slowly, and with constant stirring, into a mixture of 20 g. of anhydrous potassium carbonate dissolved in 18 ml. of cold Water, 20 g. of ice and 38 ml. of cold-chloroform. Additional amounts of solidpotas sium carbonate are added during the quench to keepjthe pH above 7. The final pH of the mixture is about' 9.

The chloroform layer is separated from the resulting mix-I ture, and the aqueous layers "are back-extracted with two 20 cc. portions ofchloroform. The combined organic layers are washed twice with water and with a saturated salt-solution. The chloroform solution is evaporated in vacuo on a hot waterbath and finally on a steamb'ath in acurrent-of nitrogen to a volume of about ml. About 25 'ml. of benzene is'added to the concentrated solution, and the mixture is allowed to stand for about two hours. The light buff crystals which'separate are washed with benzene and dried to give .23 g. of 9a-fiuoro-l,4-pregnadiene-"l1,8,17ct,2l-triol-3 ,20-dione -Z'I-acetate; yield approximately 74% of theory.

Example 8 I v A solution of 3.00 g. of 11B,12;8-epoxy-1,4-pregnadiene- 17a,21 -,di0l-3,20-di0n6 21-acetate in 18 ml. of chloroform is cooled to about 60 C. The solution isfpoured slowly into a cold (60" C.) solution containing 5 .0 ml. of tetrahydrofurjan, 3.75 ml, of chloroform, and 7.45 ml. of a solution of hydrogen fluoride in tetrahydrofuran (2:1 by weight); an additional 3.75 'ml. of cold chloroform is used to aid in the transfer of the epoxide solution.

8 about 9. The chloroform layer is separated from the resulting; mixture, and the aqueous layers are back-ex- -'tr'a'cted with two 20 cc; portions" of chloroform. The combined organic layers are washed twice with water and 'wi'th a saturated salt solution. The chloroform solution is evaporated in vacuo on a hot waterbath and finally on a s'te'ambath in a currentof nitrogen to a volume of about '10 ml; About 25 ml. of benzene is added to the concentrated solution, and the mixture is allowed to stand for about two hours. The light buff crystals which separate arexwashed with benzene and dried to give IZa-fluoro- 1,4-pregnadiene-l1B,l7a,21-triol-3,20-dione ZI-acetate. Various changes and modifications maybe made 111' carrying out the present invention without departing from the spirit and scope thereof. Insofar as these changes and modifications are within the purview of the annexed claims, they are to be considered aspart of this invention. We claim: i r

1. In the process of preparing an llfi-hyd'roxy-fluorm steroid of the pregnane'series by thereaction of hydrogen fluoride with the corresponding steroid 9,11- and 11,l2- epoxides, the improvement which comprises conducting said reaction under anhydrous conditions in solution with ahdan organic: Lewis base. J

' 2. In the process of preparing a 9oc-fluoro-l1fl-h droxy steroid of the pregnane series by the reaction of hydrogen fluoride with the corresponding 9,l1-epoxy-stero1d, the improvement which comprises conducting said reaction underanhydrous conditions in solution with a compound-formed by the reaction of hydrogen fluoride and an organic Lewis base.

3 In the process of preparing an llfi-hydro'xy-lhfluoro-steroid of the .pregnane series by the reaction of hydiogen fluoride with the corresponding 11,12-epoxysteroid, .the improvement which comprises conducting said reaction under anhydrous conditions in solution with v fluoride a compound formed by the reaction of hydrogen and an organic Lewis base. v v

4. The process whichcomprises react' g hydrogen fluoride with a 9,11-epoxy-4-pregnene under-anhydrous conditions in a halogenated hydrocarbon solvent, and in solution with a compound formed by the reaction of hy-.

drogen fluoride and an organic Lewis base, said comconditions in a halogenated hydrocarbon solvent,:and in solution with a compound formed by :thereaction of hydrogen fluoride and an organic Lewis base, said compound being soluble in said solvent, thereby producing the corresponding 12a-flnoro-4-pregnene-115-01.

6.. The process which comprises reacting hydrogen fluoride with a 9,11-epoxy-1,4-pregnadiene under'anhy- .drous conditions in a halogenatedhydrocarbon solvent,

and in solution with a compound formed by the reaction of hydrogen fiuorideand an organic Lewis base, said compound being soluble in said solvent, thereby producing the corresponding 9o'z-fluoro-l,4-p-regnadiene-115-01.

7:."The process which comprises reacting" hydrogen fluoride with an 11,12-epoxy-1,4-pregnadiene under anhydrous conditions in ahalogenated hydrocarbon solvent, an in solution with-a compound formed by the reaction 'of hydrogen fluoride and an organic Lewis base, said compound being soluble in said solvent, thereby producing the corresponding 12a-fluoro-1,{l-pregnadiene-llB-ol. 81111 the process of preparing 9a-fluoro-4-pregnenedione, the improvementwhich comprises conducting said reaction under anhydrous conditions in solutionwith a compound forrrred hy the union of hydrogen fluoride with anorga'ni'c Lewispase; s

" "9. In the p'rdcess of preparing 9ot=fiuoro-4-pregnenei a compound formed by the reaction of hydrogen fluoride 11p,17a-21-triol-3,20-dione by the reaction of hydrogen fluoride with 9,11 epoxy 4 pregnene-17a,21-diol-3,20-

dione in ahalogenated hydrocarbon solvent, the improvement which comprises conducting said reaction under anhydrous conditions in solution with a compound, soluble in said solvent, which is formed by the union of hydrogen fluoride with an organic Lewis base.

10. In the process of preparing 9a-fluoro-1,4-pregnadiene-l1,8,17a,21-triol-3,20-dione by the reaction of hydrogen fluoride with 9,1l-epoxy-1,4-pregnadiene-17a,21- diol-3,20-dione in a halogenated hydrocarbon solvent, the improvement which comprises conducting said reaction under anhydrous conditions in solution with a compound, soluble in said solvent, which is formed by the union of hydrogen fluoride with an organic Lewis base.

11. In the process of preparing 9tx-fluoro-4-pregnenellfi,l7a,21 triol-3,20-dione ZI-acetate by the reaction of hydrogen fluoride with 9,11 -epoxy4-pregnene-l7a,21- diol-3,20-dione 21-acetate in chloroform, the improvement which comprises conducting said reaction under an hydrous conditions in solution with the compound formed by the union of hydrogen fluoride with tetrahydrofuran.

12. In the process of preparing 9a-fluoro-1,4-pregnadiene-l1 3,17m,21-triol-3,20-dione 21-acetate by the reaction of hydrogen fluoride with 9,11-epxy-1,4-pregnadiene-17u,21diol-3,20-dione 21-acetate in chloroform, the improvement which comprises conducting said reaction under anhydrous conditions in solution with the compound formed by the union of hydrogen fluoride with tetrahydrofuran.

13. Indie process of preparing 9a-fluoro-4-pregnene- 11B,17a,2l trio1-3,20-dione 21-acetate by the reaction of hydrogen fluoride with 9,11 epoxy 4 pregnene-17a,21- dio1-3,20-dione 21-acetate, the improvement which comprises conducting said reaction under anhydrous conditions in solution with pyridinium fluoride.

14. In the process of preparing 9a-fluoro-4-pregnene- 11,3,17a-diol-3,20-dione by the reaction of hydrogen flucride with 913,1113-epoxy-4-pregnene-17a,2l-diol-3,20-diorie in a halogenated hydrocarbon solvent, the improvement which comprises conducting said reaction under anhydrous conditions in solution with a compound, soluble in said solvent, which is formed by the union of hydrogen fluoride with an organic Lewis base.

15. In the process of preparing 12a-fluoro-4-pregnene- 11p,21-diol-3,20-dione 21-acetate by the reaction of hydrogen fluoride with 115,125 epoXy-4-pregnene-21-ol- 3,20-dione Zl-acetate in a halogenated hydrocarbon solvent, the improvement which comprises conducting said reaction under anhydrous conditions in solution with a compound, soluble in said solvent, which is formed by the union of hydrogen fluoride with an organic Lewis base.

16. In the process of preparing 12a-fluoro-1,4-pregnadiene-l113,17u,21-triol-3,20-dione 21-acetate by the reaction of hydrogen fluoride with 11p,12,8'epoXy-1,4-pregnadiene-17a,21-dio1-3,20-dione 21-acetate in a halogenated hydrocarbon solvent, the improvement which comprises conducting said reaction under anhydrous conditions in solution with a compound, soluble in said solvent, which is formed by the union of hydrogen fluoride with an organic Lewis base.

References Cited in the file of this patent UNITED STATES PATENTS 2,730,525 Hogg Jan. 10, 1956 2,763,671 Fried et a1 Sept. 18, 1956 2,782,211 Wettstein et a1. Feb. 19, 1957 2,852,511 Fried Sept. 16, 1958 OTHER REFERENCES Fried et 21.: Jour. Am. Chem. Soc., 76: 1455-1456 (1954). 

1. IN THE PROCESS OF PREPARING AN 11B-HYDROXY-FLUOROSTEROID OF THE PREGNANE SERIES BY THE REACTION OF HYDROGEN FLUORIDE WITH THE CORRESPONDING STERIOD 9,11- ABD 11,12EPOXIDES, THE IMPROVEMENT WHICH COMPRISES CONDUCTING SAID REACTION UNDER ANHYDROUS CONDITIONS IN SOLUTION WITH A COMPOUND FROMED BY THE REACTION OF HYDROGEN FLUORIDE AND AN ORGANIC LEWIS BASE. 